Delay-Based Congestion Control for Multipath TCP
With the aid of multipath transport protocols, a multihomed host can shift some of its traffic from more congested paths to less congested ones, thus compensating for lost bandwidth on some paths by moderately increasing transmission rates on other ones. However, existing multipath proposals achieve only coarse-grained load balancing due to a rough estimate of network congestion using packet losses. This paper formulates the problem of multipath congestion control and proposes an approximate iterative algorithm to solve it. The authors prove that a fair and efficient traffic shifting implies that every flow strives to equalize the extent of congestion that it perceives on all its available paths. They call this result "Congestion Equality Principle".